A proportioning valve cooperates with a master cylinder and operates during braking to communicate less pressurized fluid to one brake assembly than to another brake assembly. The proportioning of pressurized fluid to a set of brake assemblies, generally being front disc and rear drum brakes, is provided to account for the increased braking of the front disc brakes.
The proportioning valve of the prior art is generally disposed within a housing outlet passage communicating with the rear drum brakes. As a result, the housing required structural modifications to accommodate the proportioning valve as well as a bypass valve which operates when the front disc brakes are in a failure mode so as to fully apply the rear drum brakes regardless the position of the proportioning valve.